JPH0678357A - Mobile radio communication method - Google Patents

Abstract

PURPOSE:To enhance the effect of the route diversity at maximum with respect to the mobile radio communication method implementing route diversity by plural base stations to each mobile station. CONSTITUTION:When radio base stations BS1, BS2 being connection object branches of a mobile station MS and an interference mobile station MSI and an interference radio base station BSI are in existence, signal to interference signal power ratios CIRu1, CIRu2 with respect to an up-link of the MS and signal to interference signal power ratios CIRd1, CIRd2 with respect to a down- link of the MS are measured. Then the branch whose CIRu1, CIRu2, and CIRd1, CIRd2 are reference ratios or over is selected and a best branch in them is totally decided as a connection destination branch.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile radio communication method, and more particularly to a mobile radio communication method for performing route diversity by a plurality of base stations for each mobile station.

As shown in FIG. 4, mobile stations MS _{1 to} MS _m ,
In the mobile radio system including the radio base stations BS _{1 to} BS _n and the line control station MCS, each of the mobile stations MS _{1 to} MS _m is a car phone or a mobile phone, and the radio base stations BS ₁ to BS _m are mobile phones.
It is a mobile terminal capable of wireless communication with BS _n . The circuit control station MCS is connected to a plurality of radio base stations BS _{1 to} BS _n, and is also connected to an exchange (not shown) in a fixed telephone network or a mobile network via an exchange (not shown). It also sets wireless channels, controls switching, and monitors lines.

In such a mobile radio system, a radio base
Ground station BS₁~ BS_nEach of the multiple radio base stations
Zones are designed to overlap, which causes mobile stations
MS ₁~ MS_mEach of them is in the overlapping wireless zone above
Select the wireless base station with the best line quality and connect the line.
Selective synthesis is performed. That is, this mobile radio system
Each mobile station has multiple wireless base stations
Perform route diversity for lunch. like this
Optimal branch selection is important for mobile mobile systems
Be done.

[0004]

2. Description of the Related Art FIG. 5 shows a flowchart of an example of a conventional mobile radio communication method. In the mobile radio system performing the above-mentioned route diversity, the mobile stations MS _{1 to} MS
Signal-to-interference signal power ratio (CIR) in the uplink from the mobile station to the radio base station when _m is trying to connect to each radio base station which is a diversity branch
And C in the downlink from the wireless mobile station to the mobile station.
The IR and the mobile station are respectively measured, and the measurement results in each branch are reported to the line control station MCS (step 31).

Then, the line control station MCS selects a branch in which the uplink CIR is larger than the reference CIR or the downlink CIR is larger than the reference CIR for each branch (radio base station) (step 32). First, the branch selected in step 32 is determined as the branch to be connected to the mobile station (step 33).

[0006]

However, in the mobile radio system, the uplink CIR and the downlink CIR are not generally equal to each other. Therefore, based on only one of the uplink CIR and the downlink CIR as in the conventional method. If only the branch decision is made, there is a problem that the optimality of branch selection is not guaranteed at all.

The present invention has been made in view of the above points, and a mobile radio system that solves the above problems by selecting a branch based on both the reception state of a radio base station and the reception state of a mobile station. It is intended to provide a communication method.

[0008]

The mobile radio communication method of the present invention is a mobile radio communication method for performing route diversity for each of mobile stations with a plurality of radio base stations as branches under the control of a line control station. In, a signal-to-interference signal power ratio of an uplink to a plurality of radio base stations that are connection target branches of one mobile station, and a signal-to-interference signal power of a downlink from the plurality of radio base stations to the one mobile station A branch having a reference value or more is selected for each ratio, and the best branch among the selected branches is determined as the connection destination of the one mobile station.

In addition, among the selected branches, the branch having the best uplink signal-to-interference signal power ratio,
The branch with the best downlink signal to interference signal power ratio is selected independently of each other.

[0010]

In the present invention, as shown in FIG. 1, one mobile station MS
The connection target branches of are the radio base stations BS ₁ and BS ₂ ,
It is assumed that the mobile station MSI and the radio base station BSI using the same channel are the interfering mobile station and the interfering base station, respectively, and there is no mutual influence between the uplink and the downlink. The mobile station MS moves to a position close to the radio base stations BS ₁ and BS ₂ in terms of distance.

In this case, the uplink received signal-to-interference signal power ratio (CIR) of the radio base stations BS ₁ and BS ₂ which receive the MS transmission signal is CIR _u1 in BS ₁ as shown in FIG. Further, in the BS ₂ is represented by CIR _u2, a relationship of CIR _u1> CIR _u2.

On the other hand, the downlink received signal-to-interference signal power ratio (CIR) of the mobile station MS receiving the transmission signals of the radio base stations BS ₁ and BS ₂ is determined by the reception level of the transmission signal of BS _{1 and} the transmission of BSI. There is a ratio CIR _d1 between the level at which the signal is received as an interference signal and a ratio CIR _d2 between the level at which the BS ₂ transmission signal is received and the level at which the BSI transmission signal is received as an interference signal. As can be seen from the above, there is a relationship of CIR _d1 <CIR _d2 .

According to the invention of claim 1, the above CIR_u1，
CIR_u2, CIR_d1And CIR_d2Is above the standard value
If it is above the reference value, CIR_u1And C
IR _d1Branch BS consisting of₁CIR and CIR_u2Over
And CIR_d2Branch BS consisting of₂CIR of each
BS as the branch of the connection destination₁Or BS
₂To decide.

On the other hand, in the invention described in claim 2, the above C
When each of IR _u1 , CIR _u2 , CIR _d1 and CIR _d2 is greater than or equal to the reference value, the larger one is selected for the uplink and the downlink respectively. Therefore, BS _{1 for} which CIR _u1 is obtained on the uplink and BS ₁ for the downlink are selected. BS _{2 from} which CIR _d2 is obtained is determined as a branch of each connection destination.

[0015]

FIG. 2 is a flow chart of the first embodiment of the present invention.
Indicates. In the present embodiment, the mobile radio system shown in FIG.
In this case, the line control station MCS performs branch selection control in FIG.
Follow the flow chart. First, the line control station MC
S is each mobile station MS₁~ MS _m, Wireless base station BS₁~ BS
_nFrom each branch's Uplink CIR and Downlink
The report of the measurement result of CIR is received (step 11).

[0016] Here, as an example, an uplink CI between a branch (radio base station) to which a mobile station is connected.
It is assumed that the R and the downlink CIR are reported as shown in the following table.

[0017]

[Table 1]

Next, the line control station MCS determines the uplink CI.
Only those branches where R> reference CIR and downlink CIR> reference CIR are selected (step 12). here,
Assuming that the reference CIR is 14 dB as an example, the branches A, B and C are selected in step 12 from Table 1 above.

Next | uplink CIR-reference CIR |
+ | Downlink CIR-reference CIR | = X is maximum,
The branch with the smallest | uplink CIR-downlink CIR | = Y is selected (step 13). here,
Of the branches A, B and C selected in step 12, A is X = 2, Y = 0, B is X = 12, Y = 0, C
Is X = 12 and Y = 10, the above step 13
Then, branch B is selected.

That is, the branch B is selected as a branch having a CIR that is as large as possible compared to the reference CIR and that has a small difference between the uplink and downlink CIRs. As a result, the line control station MCS connects one mobile station with the radio base station forming the branch B (step 14).

FIG. 3 shows a flowchart of the second embodiment of the present invention. In the figure, the same processing steps as those in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted. In FIG. 3, when the predetermined branch is selected in step 12, the circuit control station MCS subsequently determines the branch with the largest uplink CIR (step 21) and at the same time the downlink CIR.
The largest branch is determined (step 22).

In the example of Table 1 above, branches A, B and C are selected in step 12, so in step 21
As can be seen, branch C is selected, and in step 22, branch B is selected. When there are a plurality of branches having the maximum uplink or downlink CIR value, any one of them is selected.

In this way, in this embodiment, the line control station MCS connects the uplink of one mobile station to the radio base station forming the branch C (step 23), and the downlink forms the branch B. A line connection is established with the wireless base station (step 24).

[0024]

As described above, according to the present invention, the best branch is selected comprehensively from the branches having the reference value or more for each of the uplink CIR and the downlink CIR. This allows for a more optimal route diversity branch decision and also provides maximum CI separately for each uplink and downlink CIR.
Since the branch having R is selected, it has a feature that the effect of route diversity can be maximized.

[Brief description of drawings]

FIG. 1 is an explanatory view of the operation of the present invention.

FIG. 2 is a flowchart of the first embodiment of the present invention.

FIG. 3 is a flowchart of a second embodiment of the present invention.

FIG. 4 is a configuration diagram of a mobile communication system to which the present invention is applied.

FIG. 5 is a flowchart of an example of a conventional method.

[Description of Codes] MS, MS _{1 to} MS _m mobile station BS _{1 to} BS _n radio base station MCS line control station MSI interfering mobile station BSI interfering radio base station 11 to 14, 21 to 24 steps

Claims (2)

[Claims] 1. Route diversity for each of the mobile stations (MS _{1 to} MS _m ) having a plurality of radio base stations (BS _{1 to} BS _n ) as branches is performed under the control of a circuit control station (MCS). In a mobile radio communication method, an uplink signal-to-interference signal power ratio for a plurality of radio base stations (BS ₁ , BS ₂ ) that are connection target branches of one mobile station (MS), and the plurality of radio base stations (MS BS ₁ ,
BS ₂ ) selects a branch having a reference value or more for each of the downlink signal-to-interference signal power ratios for the one mobile station (MS) (12), and selects the best branch among the selected branches as the one movement. A mobile radio communication method, characterized in that a connection destination of a station (MS) is determined (13, 14). 2. Among the selected branches, the branch having the best uplink signal-to-interference signal power ratio and the branch having the best downlink signal-to-interference signal power ratio are independently connected to each other. The mobile radio communication method according to claim 1, wherein the determination (21 to 24) is made.